The object of the proposed research is to investigate the role of adenosine 3', 5'-monophosphate (cyclic AMP) in the effects of ethanol on the brain. Results of our experiments indicate that ethanol has differential and specific effects on the cyclic AMP system in various brain areas. Cyclic AMP levels in the cerebellum was decreased after acute ethanol administration and increased after chronic ethanol ingestion. Ethanol also blocked postdecapitation rise of cyclic AMP levels in the cerebrum and cerebellum. Pentobarbital, in a dose which produced similar central depression, also decreased cyclic AMP level in the cerebellum but it did not prevent postdecapitation rise of cyclic AMP in the cerebrum and cerebellum. These results will serve as a basis for further investigation. Ethanol effects on the cyclic AMP system in specific brain areas or structures will be studied in greater detail and the mechanism by which ethanol causes cyclic AMP changes will be investigated. The relationship between cyclic AMP changes and behavioral effects induced by ethanol will be studied, and attempts will be made to modify these changes by treatment with other drugs.